Lonni Sue Johnson was a successful illustrator — think New Yorker covers — amateur violist, pilot, and small businesswoman. When the herpes simplex virus attacked her brain, it caused substantial tissue loss in her medial temporal lobes; she lost almost her entire lifetime of knowledge and experiences, along with the ability to form new memories. In Aeon, Michael Lemonick describes how she’s invaluable to neuroscientists working to understand how we make, organize, and store memories.

There’s no established protocol, however, for probing an amnesia victim on the sorts of knowledge Johnson gathered in her lifetime. The neuroscientists at Johns Hopkins started at the most basic level they could think of – the ‘Who painted this?’ test, which she pretty much failed. Her semantic memory about art and artists, her primary area of expertise, was significantly impaired. Remarkably, though, when the scientists included some of her own artworks in the testing, she correctly flagged every one as hers. Even more surprising, when the researchers added drawings done in a style somewhat similar to Johnson’s, she picked them out as artworks she might have produced. To do so, she had to be drawing on some sort of memory. It clearly wasn’t episodic memory, since artworks aren’t events – but it’s unclear that it qualifies as semantic memory either, since it addresses an ineffable quality, not a set of facts. ‘I don’t think we know how to characterise that sort of memory,’ Barbara Landau, one of the Johns Hopkins scientists, told me in an interview.

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